Adaptive human behavior and delays in information availability autonomously modulate epidemic waves

Abstract The recurrence of epidemic waves has been a hall-mark of infectious disease outbreaks. Repeated surges in infections pose significant challenges to public health systems, yet the mechanisms that drive these waves remain insufficiently understood. Most prior models attribute epidemic waves to exogenous factors, such as transmission seasonality, viral mutations, or implementation of public health interventions. We show that epidemic waves can emerge autonomously from the feedback loop between infection dynamics and human behavior. Our results are based on a behavioral framework in which individuals continuously adjust their level of risk mitigation subject to their perceived risk of infection, which depends on information availability and disease severity. We show that delayed behavioral responses alone can lead to the emergence of multiple epidemic waves. The magnitude and frequency of these waves depend on the interplay between behavioral factors (delay, severity, and sensitivity of responses) and disease factors (transmission and recovery rates). Notably, if the response is either too prompt or excessively delayed, multiple waves cannot emerge. Our results further align with previous observations that adaptive human behavior can produce non-monotonic final epidemic sizes, shaped by the trade-offs between various biological and behavioral factors–namely, risk sensitivity, response stringency, and disease generation time. Interestingly, we found that the minimal final epidemic size occurs on regimes that exhibit a few damped oscillations. Altogether, our results emphasize the importance of integrating social and operational factors into infectious disease models, in order to capture the joint evolution of adaptive behavioral responses and epidemic dynamics. Significance statement We develop a behavioral-epidemiological framework in which individuals adjust their level of risk mitigation (e.g., social distancing, mask-wearing) based on both the available information and their perceived risk of infection. We show that the feedback loop between infectious disease dynamics and human behavior can autonomously produce multiple epidemic waves. The disease dynamics are strongly influenced by the interplay between the timing, severity and sensitivity of behavioral responses, as well as transmission and recovery rates. Moreover, our results confirm that adaptive human behavior can produce non-monotonic final epidemic sizes, which we show is due to oscillatory epidemic dynamics. Interestingly, we found that in the absence of interventions, the minimal final epidemic size occurs on regimes exhibiting a few damped oscillations.